The present invention relates to a printer system comprising a host device and a host based printer (i. e., a host based printer system), and more particularly relates to a technique suitable for a host based printer which receives compressed data of a printed image from a host device, expands this compressed data so that the printed image is restored, and performs printing on the basis of this printed image.
Ordinarily, in host based printer systems, a framework is adopted in which 1) rasterizing processing (development into a bit map) is performed in a host device on printing data that includes text, figures, images and the like, so that a printed image is produced, 2) the printed image is transferred from the host device to a host based printer, 3) in this host based printer, a controller transfers the printed image to a printing engine in accordance with the synchronizing signal of this printing engine, and 4) the printing engine performs printing.
Here, in the host based printer, in cases where the reception rate of the data from the host device is slower than the printing rate of the printing engine, a construction is ordinarily used in which the received data is temporarily stored in a receiving buffer inside the host based printer so that the data does not become exhausted during printing, and printing is started at a point at which at least a certain amount of data has been stored in this receiving buffer.
In cases where such a construction is used, a method has been proposed in which printing is started before a printed image corresponding to one page has been received, in order to shorten the waiting time from the point in time at which a printing command is received to the point in time at which printing is actually started. For instance, in cases where the transfer and the like of printed image are performed in band units, it is conceivable that a timing at which the number of bands that have been received reaches a predetermined proportion of the total number of bands may be taken as the timing at which printing is started (for example, printing is started at the point in time at which 1/10 of the bands corresponding to one page are received in a host based printer).